/Engine/Source/Editor/UnrealEd/Public/Tools/UEdMode.h
Registers and maps the provided UI command to actions that start / stop a given tool. Later on this UI command can be referenced to add the tool to a toolbar.
virtual void RegisterTool ( [TSharedPtr](API\Runtime\Core\Templates\TSharedPtr)< [FUICommandInfo](API\Runtime\Slate\Framework\Commands\FUICommandInfo) > UICommand, [FString](API\Runtime\Core\Containers\FString) ToolIdentifier, [UInteractiveToolBuilder](API\Runtime\InteractiveToolsFramework\UInteractiveToolBuilder) * Builder, EToolsContextScope ToolScope )